Before a document image is printed out, a user often causes an image forming apparatus, such as a copying machine and a multifunction printer, to print-preview the document image that has been image-processed in accordance with a processing condition set by the user. In a case where a plurality of documents are read, each of the documents may be print-previewed one by one, or the plurality of documents may be print-previewed collectively. The processing condition includes: a sort of a document; a print density; a ratio in enlarging/reducing processing; single-sided printing or two-sided printing; a binding margin size; and the like.
For example, Patent Literature 1 described below discloses an image forming apparatus which (i) print-previews an inputted document image, and also (ii) displays a checking icon with which a user can check whether or not a page orientation of the document is correct. Specifically, this checking icon is an icon for accepting a command to carry out rotation processing and a setting of a rotation angle. Settable rotation angles are 0°, 90°, 180°, and 270°. Further, in the image forming apparatus disclosed in Patent Literature 1, a rotation direction is a clockwise direction. If a user wants to rotate a document image at a right angle, the user sets the rotation angle at 90°, and if the user does not want to rotate the document image, the user sets the rotation angle at 0°.
Patent Literature 1 discloses that when receiving a command to carry out the rotation processing from a user, the image forming apparatus carries out the rotation processing with respect to a document image, and then print-previews again the document image that has been subjected to the rotation processing, before the document image is printed out. Further, Patent Literature 1 discloses that the image forming apparatus (i) determines the page orientation of the inputted document image, (ii) carrying out the rotation processing based on the determined page orientation, and (iii) print-previews the rotation-processed document image. Furthermore, Patent Literature 1 discloses that the image forming apparatus print-previews a image in which a plurality of document images are shown collectively, and carries out the rotation processing collectively with respect to the plurality of document images.